boostin05blacksti

Ok guy/gals. Ive run into a problem that I can't seem fix. I've talked to some people in the industry and no one has any solid answers. Btw thanks for your time Travis! I bought a gm crate lsx454 straight for gm. Come with the harmonic balancer already installed. I then found a full used setup and bought it all (was told it had very low miles). That whole set up came with a harmonic balancer but I decided to run the one that came with the motor. So when I brought the car to the tuner for the first time and he was trying to do the crank relearn (revs the motor up to 4k) he says it threw the belt due to it not being in line. That the crank is sunk in 1/4". So I get the car back and take look..now I come to the conclusion it was one of two things. Either the crank is in too far causing it to throw the belt or when the motor torqued the belt touched the upper control arm on the drivers side and caused it to throw it.(which I plan to file down some more- has about 1/2-3/4" of clearance ATM.)


So being that I had the other harmonic balancer I decided to change it to the one that came with the assessories. Changed it out and here's a comparison.
One that came with the lsx454 motor on the left and one the left the one that I bought as a kit used.









So I swapped them out and figured the problem was solved. Go to start the car this past saturday and I can hear a repeatedly slapping. Go to the front of the motor to see the passenger tensioner slapping repeatedly and the belt going in and coming off the harmonic balancer is almost ribbing in a way like its trying to walk off but is not. But it does not throw the belt. On Sunday I start the car again.. This time no slapping of any kind and seems to be on just fine.. Started the car again later on Sunday same thing..totally fine. I'm lost on what to do..aside front buy a whole new front end setup. The only thing I can think now is to shave the mounting bracket that houses the alternator, power steering pump and drivers tensioner. I'm thinking shaving the back side a 1/4 " will help the problem...any one have any suggestions or input it would be greatly appreciated. Thanks Steven


One with the old harmonic balancer:

bww3588

iTrader: (49)

You have a Corvette front accessory drive...are you sure your balancers are from a Corvette as well?

boostin05blacksti

Yes, I had the one that came with the gm crate motor on there before and then I switched that out for the one that I bought used as shown in the above pictures compairing them.

S10xGN

iTrader: (11)

Those balancers look the same to me, as far as offset. You need to measure from the front face to the rear (inner) edge. As it lays on the table, measure using a depth mike from the table to the upper tip from inside the bore. Sounds like your balancer isn't pulled on fully, check how far the crank is recessed inside the pulley bore, should be < 1/8". Use a straightedge across all the pulleys to check the alignment.